In order to encourage shares by your friends on your Facebook Friend / Timeline page, you need to make sure you change your privacy settings to Public. Even if you don't change it for all posts, you need to change it on the individual posts where you are telling people about your upcoming or new release.

If you don't set it to Public, when it is shared, the person sharing will see this warning: "Some people may not be able to see this attachment because of its privacy settings."

What that means is only your MUTUAL Friends will see the shared post.

Anything you hope will be shared should be set to Public. This way, you will also reach the friends of those who have shared for you, reaching even more potential readers.